I want to have several dump truck loads of sand hauled in to make a nice beach. Would you put plastic down on the shore and then put the sand on top? Also what can I put out in the pond on the bottom, to make a rim, so the sand doesn't wash on out to the deep part.

Does your pond have water in it currently? If not, the easiest way would be to create a shelf with a ledge then put down geotextile cloth then dump the sand on top of the cloth.

Another vote for the Geotextile fabric. If there's water in the pond, use cinderblocks, lay the Geotex over the blocks.

Thanks guys. The pond is dry so I will use the geotextile. I appreciate it!

Another question guys. Should I cover the whole area with the geotextile fabric including in the water and out of the water?

I would.